Population

Population

No population estimates exist for Spanish Hogfishes, but an approximate estimate may be derived under very loose assumptions based on the number of individuals as the product of density, distribution area and sighting frequency (as an indication of the probability of occupancy at an area). N= Density*Distribution area*SF%

Assumptions: 1. The average density of the animal is around 0.025/100 m2. Three estimates of density are available in the relevant literature, although of which two are from a single locality at one time (2.8 /100 m2, Pattengill-Semmens 2000, 0.5/100 m2, Brosnan et al 2002 and 0.025/100 m2, Opitz 1996). The 0.025/100 m2 density was chosen since it applies to the Caribbean locality, which constitutes the majority of the distribution. However, as the estimates clearly indicate, density distribution is extremely patchy and the average density across the entire distribution could be vastly different.

2. The fish is commonly and almost exclusively associated which coral reef habitats across its distribution (Gomon 2006). Therefore the total area of coral reef is taken as habitat range, which totals 26,960 km2 for the Caribbean and the Atlantic Brazilian coast.

3. The species occurs in low densities, and abundance is extremely patchy. Therefore sighting frequency for a particular site will be treated as probability of occurrence in a site. In this case, SF% is around 57% as average of respective SF% in different areas averaged over the known record (REEF, accessed May 4th, 2008).Upon such assumptions, the estimated total number Spanish Hogfish is ~3,841,800 individuals. Confidence limits cannot be stated but the estimate is clearly based on very loose assumptions. In order to better grasp the overall picture of population trends, density needs to be systematically sampled for larger areas to eliminate variations between sites. More study is needed research into variability in habitat use at different sites in order to make the estimate of total population size more rigorous.